Regarding Bob Greaves, I'm guessing it was a way to keep him on the programme after he stopped doing the news
Bob did a load of other things for Granada at the time, and of course returned to being main presenter when John Huntley left, but in that period he was a bit of a presenter-at-large and would just pop up doing pretty much whatever he fancied, the sort of character all regional news programmes seemed to have in those days and they thrived on. Greaves and Hall together was a big deal for Granada, they talked it up like it was Lennon meeting Jagger, the two big regional news characters together at last. Hall had left BBC North West under a bit of a cloud I think after he got nicked for shoplifting (though obviously, they didn't know the half of it), but it's hard to imagine a bloke with a medallion saying "'ey up, love!" really thriving at John Birt's BBC.
Seems to me that some BBC regions were better than others. BBC East were down the lower end. Mercifully, I think BBC North West were one of the better ones. The 1988 'bonking worms' NWT titles were probably their best...
https://www.tvark.org/?page=media&mediaid=106097
I grew up with those bonking worms titles, that seems the definite NWT title sequence and theme tune to me. I know the woosh at the start is a bit ridiculous, and the set looks like a padded cell, but I still think they look quite good and the theme is nice.
Another classic example of 'we've now got a computer than can do 3D animation, so we are going to use every single feature available'
This thread always seems to be alighting on Central, but we could pick it up and so I'd sometimes flick over to them. I always thought the titles 3:30 into here are a great example of that, the logo animating on, exploding and then being put back together again, just because it can.
That does remind me though of Peter Snow being interviewed about the election night graphics in 1992, and being asked why they span around, and he said "They spin round because we can make them spin round, and at three in the morning you've got to do something to keep people interested!".